Lattice dynamics of boron nitride

Using the density-functional theory within the full potential linear augmented plane-wave (FP-LAPW) method, we have calculated ab initio the equation of state and the principal phonon modes in cubic boron nitride (c-BN), including their pressure dependence and the amplitude of the eigendisplacements. A good agreement with the experiments is obtained, whenever a comparison is possible: in fact, most of the results are predictions. A ten-parameter valence overlap shell model (VOSM) was constructed and we obtained the phonon dispersion curves, elastic constants and effective charges. Our results were compared with calculated theoretical data for c-BN and for other III–V materials and we found that the lattice dynamics properties for cubic boron nitride is very close to those of diamond.